#1 ADU Contractor in Westminster
Custom Builds by Horizon Remodeling
Horizon Construction & Remodeling Inc. builds accessory dwelling units in Westminster, managing design, permitting through the City of Westminster Building Division, budgeting, and material selection on a single contract. Most homes here are modest postwar tract houses on flat suburban lots, and those level yards often give us a straightforward footprint to work with for a detached unit or backyard cottage. We coordinate every licensed trade required to meet California building code and any applicable association rules, keeping the project moving from the first plans through the final inspection.
Services We Offer
How Our ADU Process Works
When it comes to enhancing your living space, room additions combined with Accessory Dwelling Unit (ADU) construction offer unparalleled versatility and value. These projects not only increase square footage but also provide additional living accommodations, whether for extended family, rental income, or work-from-home setups, making them a popular choice for homeowners seeking to maximize their property’s potential. According to California’s Department of Housing and Community Development, ADUs are a key solution to expanding housing options in urban and suburban neighborhoods.
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If you are looking for an adu contractor in Westminster, understanding how state ADU law and local permitting work together is a good place to start. California Government Code sections 66310 through 66342 govern the process, and a update effective January 1, 2026 changed how square footage is measured, now counting only interior livable space. Under that same law, the city has 15 business days to confirm an application is complete and 60 days to approve or deny it, and approval is ministerial, meaning no public hearing and no discretionary design review.
Applications in Westminster go through the Building Division inside the Community Development Department. No unusual local overlay applies here, so the standard building code and any applicable association rules are what actually govern your project. That keeps the process relatively straightforward compared to cities with additional local restrictions layered on top of state requirements.
Westminster’s housing stock shapes a lot of the practical decisions. Most homes are modest postwar tract houses on flat suburban lots, built during the 1950s and 1960s when the city’s population climbed from roughly 25,000 to over 60,000. That lot geometry determines setbacks, how far utility lines need to run, and whether a detached new build or a garage conversion makes more sense for your property. We walk the parcel first and check all of that before a single line gets drawn.
State law sets a floor of protections regardless of where the parcel sits. A local agency cannot cap an ADU below 850 square feet of interior livable space, or 1,000 square feet for a unit with more than one bedroom. Side and rear setbacks cannot exceed four feet, owner-occupancy cannot be required, adding an ADU cannot trigger a fire sprinkler retrofit of the main house, and there are no impact fees on units of 750 square feet or less.
Other Remodeling Services We Offer
A modern kitchen adds functionality, comfort, and lasting value to your home. At Horizon Construction & Remodeling, our kitchen remodeling experts bring fresh ideas and professional project management tailored to your unique needs. From layout design to material selection, we prioritize delivering a high-standard kitchen that’s both beautiful and energy-efficient — enhancing the way you cook, gather, and live every day.
Whether you envision a classic Southern California pool or a fully customized backyard oasis, Horizon Construction & Remodeling delivers the highest level of quality and service. Our comprehensive pool design and remodeling services cover everything from layout and decking to built-in BBQs and final touches like landscaping. Let Horizon be your trusted partner in transforming your backyard into the perfect outdoor retreat.
If you are planning a complete bathroom remodel or simply want to change your tub, shower, update your plumbing fixtures, or make the space more efficient, our team at Horizon will help you through the process with expert advice, professional craftsmanship, and affordable options with beautiful results. Learn more about our bathroom remodeling services.
Transform your space with our expert interior work services. We offer a comprehensive range of solutions — from space planning and custom design to the selection of high-quality finishes and materials. Our team of experienced professionals works closely with you to create a space that’s both functional and stylish, tailored to your unique needs, goals, and budget. Whether you’re updating a single room or overhauling your entire interior, we bring precision, creativity, and craftsmanship to every project.
At Horizon, we believe your home is more than just four walls — it’s where life happens. It’s the place you relax, gather with family and friends, and create lasting memories. That’s why we offer a full range of exterior work services designed to elevate your outdoor living space. From patios and hardscaping to custom decks and exterior renovations, we help turn your vision into a dream yard that complements your lifestyle and enhances curb appeal.
At Horizon Construction & Remodeling, our expert team includes a dedicated design and planning division that works hand-in-hand with licensed architects and structural engineers. We take care of everything — from detailed plans and blueprints to securing city permits — so you don’t have to deal with delays or red tape. Our goal is to streamline the process and provide a fully approved set of documents that aligns with both your vision and city regulations, saving you time and stress.
Why Choose Horizon Remodeling As Your ADU Contractor in Westminster ?
Horizon Construction and Remodeling is a licensed Class B general building contractor, bonded, and based out of Fullerton, a short drive from Westminster. We have been doing design-build work since 2009, and ADUs are a natural fit for the flat suburban lots that define most of this city. The postwar tract homes built during Westminster’s rapid growth in the 1950s and 1960s typically sit on parcels with usable rear yard space, which is exactly where a detached ADU belongs.
A detached ADU is a complete small dwelling: foundation, framing, roof, electrical, plumbing, kitchen, and bathroom, all placed behind an existing home. Because design decisions and construction constraints are the same decisions, one company handling both produces a tighter result. Permits go through the City of Westminster Building Division within the Community Development Department, and we prepare that submittal as part of the same process rather than as a separate step.
We work throughout Westminster, including Little Saigon, Barber City, the Bolsa Avenue corridor, and the Civic Center area, as well as nearby Midway City, Garden Grove, and Stanton.
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ADU Contractor Services in Westminster
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ADU Contractor in Westminster FAQ
What is an ADU and why should I build one?
An accessory dwelling unit is a secondary home on your property, built as a backyard cottage, garage conversion, or in-law suite. Working with Horizon Construction and Remodeling on an ADU in Westminster lets you add rental income, house extended family, or gain extra living space on the flat suburban lots that define this city’s postwar tract neighborhoods.
How much does it cost to build an ADU in California?
ADU costs in Westminster vary based on factors we cannot pin down from a web page alone. The size of the unit, whether you are converting an existing structure or building new detached construction, the utility runs your specific lot requires, and the finish level you choose all move the number significantly. What we can tell you is how the law works in your favor. State rules limit impact fees for units at or under 750 square feet of livable space, school fees apply only above 500 square feet, and connection fees for a conversion or junior ADU are restricted because state law does not treat those as a new residential use. An ADU also cannot legally trigger a fire sprinkler retrofit of your main house.
Westminster’s typical postwar tract homes on flat suburban lots often have straightforward site conditions, but every parcel is different, and permits go through the City of Westminster Building Division within the Community Development Department. Setbacks, utility placement, and lot coverage still need to be verified on-site before any price means anything. We walk the property, confirm those details, and then give you a fixed scope you can hold us to. One point worth stating clearly: the CalHFA ADU grant program is closed and fully allocated, and the agency itself warns that offers to help you obtain that grant are scams.
Do I need permits for an ADU in Westminster?
An ADU always requires a building permit, but the approval process is ministerial rather than discretionary, meaning no hearing or design review board gets involved. In Westminster, applications go through the City of Westminster Building Division within the Community Development Department, and state law sets firm deadlines: 15 business days to confirm completeness and 60 days to approve or deny, shortened to 30 days when a pre-approved plan is used. The postwar tract homes that define most Westminster neighborhoods typically sit on flat lots that suit a straightforward ADU layout. Horizon prepares and submits the full permit package and follows it through every inspection, so the process does not fall back on the homeowner.
How long does ADU construction take with Horizon Remodeling?
Most ADU construction projects take between 4 to 8 months from design to completion, depending on scope and permit approvals. Horizon Remodeling prioritizes efficient timelines while maintaining quality workmanship.
What types of ADUs can Horizon Remodeling build?
We specialize in building detached ADUs, attached ADUs, garage conversions, backyard cottages, and junior ADUs (JADUs). Our team can help you choose the right ADU style for your property and goals.
Can I build a detached ADU on my property in Westminster?
Yes, if your property meets California zoning and space requirements. Horizon Remodeling will assess your site, secure the necessary permits, and build a fully detached ADU tailored to your preferences.
Is Horizon Remodeling licensed to build ADUs in my area?
Yes, Horizon Remodeling is fully licensed, bonded, and insured to build ADUs throughout Orange County and surrounding areas. We have over 18 years of experience delivering high-quality ADU projects.
What are the benefits of hiring Horizon Remodeling for my ADU project?
Horizon Construction & Remodeling Inc. handles ADU design, permitting through the City of Westminster Building Division, and construction from start to finish, keeping the project on budget and built to code on the flat postwar lots that define most of the city.
Does Horizon Remodeling handle ADU design and permitting?
Absolutely! Horizon Remodeling provides complete ADU design services, including architectural plans and 3D renderings. We also handle city permits and inspections, streamlining your project and reducing stress.
How do I get started on an ADU with Horizon Remodeling?
Ready to move forward with an ADU in Westminster? Contact Horizon Construction & Remodeling Inc. to schedule a free consultation, where we assess your property, discuss your goals, offer design recommendations, and deliver a detailed project estimate.
Recent ADU and Garage Conversions
Three completed ADU and garage conversion projects from our Orange County portfolio. Every project below was built in San Clemente. Nothing loads from YouTube until you press play.
ADU project in San Clemente
ADU project in San Clemente
ADU project in San Clemente
Built by Horizon Construction & Remodeling, Inc. Licensed Class B general building contractor.
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Horizon is a licensed Class B general building contractor serving Westminster and the surrounding Orange County communities.
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